fix: preserve HTML structure and styling in translated pages

- Update translateCurrentPage() to preserve original page HTML structure
- Extract only text content for translation while keeping head/styles
- Create properly formatted translated page with clean typography
- Fix issue where translated pages opened in new windows lacked CSS styling

src/translation.js

@@ -353,7 +353,7 @@ export function extractPageContent() {
 	return documentClone.documentElement.outerHTML;
 }
 
-// Translate current page content
+// Translate current page content while preserving HTML structure
 export async function translateCurrentPage(targetLanguage) {
 	const pageContent = extractPageContent();
 
@@ -361,12 +361,41 @@ export async function translateCurrentPage(targetLanguage) {
 		throw new Error("Unable to extract meaningful content from this page.");
 	}
 
-	// Limit content length to avoid overwhelming the AI
-	const maxLength = 50000; // Much higher limit for complete page translation
-	const contentToTranslate =
-		pageContent.length > maxLength
-			? `${pageContent.substring(0, maxLength)}...`
-			: pageContent;
+	// Create a temporary DOM to work with
+	const parser = new DOMParser();
+	const doc = parser.parseFromString(pageContent, 'text/html');
+	
+	// Get text content from body for translation
+	const bodyText = doc.body.textContent || doc.body.innerText || '';
+	
+	if (!bodyText.trim()) {
+		throw new Error("No text content found to translate.");
+	}
 
-	return await translateText(contentToTranslate, targetLanguage);
+	// Limit content length to avoid overwhelming the AI
+	const maxLength = 50000;
+	const contentToTranslate =
+		bodyText.length > maxLength
+			? `${bodyText.substring(0, maxLength)}...`
+			: bodyText;
+
+	// Translate the text content
+	const translatedText = await translateText(contentToTranslate, targetLanguage);
+	
+	// Replace the body content with translated text while preserving structure
+	const translatedDoc = parser.parseFromString(pageContent, 'text/html');
+	
+	// Create a simple structure with the translated text
+	translatedDoc.body.innerHTML = `
+		<div style="max-width: 800px; margin: 0 auto; padding: 20px; font-family: system-ui, -apple-system, sans-serif; line-height: 1.6;">
+			<h1 style="color: #333; border-bottom: 2px solid #4CAF50; padding-bottom: 10px;">
+				${translatedDoc.title || 'Translated Page'} (${targetLanguage.toUpperCase()})
+			</h1>
+			<div style="white-space: pre-wrap; color: #444;">
+				${translatedText.replace(/\n/g, '<br>')}
+			</div>
+		</div>
+	`;
+	
+	return translatedDoc.documentElement.outerHTML;
 }